Piracy concerns in connection with the theatrical exhibition of motion picture films are at the forefront of concerns for the motion picture industry. Once a film distributor distributes prints of a motion picture film to exhibitors for theatrical exhibition, often a certain degree of control over the product is lost. For example, in the regular course of exhibiting the film in a theater, whether analog or digital, a customer in the theater may surreptitiously record the film using, for example, a hand held camcorder during the presentation. At a more sophisticated level, a person seeking to obtain an illegal copy of a film print may gain access to a theater projection booth in collusion with an employee of the exhibitor and make a copy of the film after hours in a relatively controlled environment. In such an environment, the audio from the projection equipment can be directly fed to the camcorder and a tripod can be used to ensure a clear and steady picture. As a result, an illicit copy of relatively high quality can be made. Furthermore, the print may also be scanned to create a video master.
Such illicit “pirate” copies of a movie can then be distributed over the Internet or by using hard copies (video CDs or DVDs), and this reduces the economic value of the legitimate film distribution. With the advent of the Internet and affordable higher quality recording devices, this problem has become increasingly severe in recent years. Thus, a method for tracing the origins of the illegal copies is highly desirable.
In 1982, the Motion Picture Association of America (MPAA), together with the Kodak™ Corporation, developed a technology for uniquely identifying film prints. This technology is commonly known as Coded Anti-piracy (CAP) coding. The code is a series of faint dots in the picture that are added as the print is manufactured. Approximately one out of every hundred frames contains four tiny dots that have been added to the image. Generally, 11 CAP-coded frames are required to reconstitute the serial number of the movie print. Each unique configuration of dots corresponds to a print identifier. The film prints are usually coded for each particular theater in which a film is distributed.
In the past, aiming an analog camcorder at a theater screen produced a poor quality, flickering image, but the coding dots usually survived the copying and reproduction process so that the serial number of the movie print could be obtained. However, the advent of digital video compression and distribution technologies has diminished the viability of CAP coding. Improved digital camcorders not only take higher quality pictures, but video compression algorithms, which are commonly employed when the pirated film is stored in a digital format or transported over the Internet, tend to obliterate the CAP codes. Specifically, because the dots representing the code are extremely small and diffuse, they are susceptible to disintegration during video compression. Furthermore, the loss of a single CAP code dot during image compression can defeat the CAP coding scheme because the CAP code is represented by spatial image placement within the film frame. Indeed, CAP coding is dependent upon 100% image survival. However, increasing the frequency of code image repetition in CAP coding systems increases the likelihood that the public will see the image. This is undesirable as it can distract viewers from the film content or cause them to form an opinion that a particular theater shows poor quality prints.
In an attempt to correct the deficiencies of the prior art, both Technicolor™ and Deluxe™ film laboratories have introduced newer systems that improve upon CAP coding. These systems place different patterns of dots in different frames of the film to be marked, and use these patterns to encode a serial number for the print. However, in such systems the locations of the marks within a frame have either been uncontrolled or fixed, which limit the capabilities of the new marking techniques.
As such, a method and system are needed for marking a film in a manner that provides a marked film which is robust and durable, avoids the limitations and deficiencies of CAP coding, and provides markings which survive pirating and compression, yet which are invisible to a viewer.